Hamburger patties are frequently manufactured at a central location, using high-speed high-volume patty molding machines, and subsequently distributed to restaurants, grocery stores, and other retail outlets. Patties of flaked or shredded meat, fish, and vegetable foods may also be handled in this manner. The term "food product", as used in this specification and in the appended claims, refers to any of the various foods identified above and to others having similar properties.
In many high-volume patty molding machines, the food product is fed from a supply hopper into a food pump that pumps the food product, under pressure, into a mold cavity in a mold plate. The mold cavity is actually an aperture extending completely through the mold plate. The mold plate is moved cyclically, between two surface closure plates, from a fill position to a discharge position and back to the fill position.
These high-volume patty molding machines can produce food patties of widely varying peripheral shapes. The most frequently used shape is of circular outline, but square, rectangular, oval, parallelogram, and irregular configurations are easily obtained. The main surfaces of the patties, however, are always flat. Relatively low-volume machines capable of producing food patties with non-planar main surfaces have been proposed; as an example, see Peterson U.S. Pat. No. 3,913,175. But there has been no mold assembly for a high-volume sliding mold plate patty molding machine capable of providing anything other than flat main surfaces on the patties.